Tailoring the Pore Size, Basicity, and Binding Energy of Mesoporous C3N5 for CO2 Capture and Conversion

Abstract We investigated the CO 2 adsorption and electrochemical conversion behavior of triazole‐based C 3 N 5 nanorods as a single matrix for consecutive CO 2 capture and conversion. The pore size, basicity, and binding energy were tailored to identify critical factors for consecutive CO 2 capture and conversion over carbon nitrides. Temperature‐programmed desorption (TPD) analysis of CO 2 demonstrates that triazole‐based C 3 N 5 shows higher basicity and stronger CO 2 binding energy than g‐C 3 N 4 . Triazole‐based C 3 N 5 nanorods with 6.1 nm mesopore channels exhibit better CO 2 adsorption than nanorods with 3.5 and 5.4 nm mesopore channels. C 3 N 5 nanorods with wider mesopore channels are effective in increasing the current density as an electrocatalyst during the CO 2 reduction reaction. Triazole‐based C 3 N 5 nanorods with tailored pore sizes exhibit CO 2 adsorption abilities of 5.6–9.1 mmol/g at 0 °C and 30 bar. Their Faraday efficiencies for reducing CO 2 to CO are 14–38% at a potential of −0.8 V vs. RHE.